Estradiol is the major oestrogen in pre-menopausal women. Ethinylestradiol has similar actions as oestradiol. It is responsible for the development and maintenance of female reproductive system and secondary sexual characteristics. It also inhibits anterior pituitary by negative feedback effect and causes capillary dilation, fluid retention and protein anabolism.
Lynestrenol is a progestogen structurally related to norethisterone. It may be used alone or as the progestogenic component of some oral contraceptives.